Portable handheld work apparatus are held and guided by an operator at one or several handles during operation. The drive motor and a tool driven by the drive motor generate vibrations which are transmitted to the handles and from there to the hands of the operator. For precise and non-tiring work, a lowest possible vibration level in the area of the handles is strived for.
A great many antivibration units are known for the vibration decoupling connection of two component assemblies of the work apparatus, such as a motor assembly and a handle assembly. The use of rubber elements as antivibration elements is widespread. These rubber elements are matched to the vibration behavior of the work apparatus with respect to their stiffness and their material damping. The high transverse contraction number of the rubber material leads to a high transverse expansion during an axial loading of the rubber antivibration element for which a corresponding structural space must be made available. The spring/damper characteristic of the rubber material changes with the excitation frequency which operates thereon. An increase of the dynamic stiffness occurs with increasing excitation frequency. A static configuration is to be selected, which is very soft at rest without influence of the dynamic stiffness increase, in order to achieve an adapted, adequately soft matching adapted to the operating frequencies of the work apparatus. The low static stiffness can act disadvantageously on the guiding accuracy of the work apparatus. A compromise between guiding accuracy and vibration decoupling has to be found in the configuration.
Furthermore, antivibration elements in the form of a spiral spring made of steel wire are known. A matching of the vibration system is comparatively simple because of the linear spring characteristic which is essentially independent of frequency. However, the large required axial space needed for the spring is disadvantageous.